/*Copyright [2019] housepower

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package impls

// StringColumn type
type StringColumn struct {
}

// Name of this column
func (c *StringColumn) Name() string {
	return "String"
}

// DefaultValue of string column is empty string
func (c *StringColumn) DefaultValue() interface{} {
	return ""
}

// NewStringColumn returns instance of string column
func NewStringColumn() *StringColumn {
	return &StringColumn{}
}

// only judge string column
func (c *StringColumn) GetValue(val interface{}) interface{} {
	switch v := val.(type) {
	case string:
		return v
	default:
		return ""
	}
}
